It is well known that the show's creators based each bending style on an existing martial art. Waterbending was based off link, Earthbenders off link, for the most part, Firebenders off link and Airbenders link.

While ATLA focused on mastering these fighting styles in a physical sense that is only on single facet of the training that goes into becoming a master of the martial arts. Body is the easiest. Mind was covered though the opening of the link, a real concept featured in tantric and yogic traditions of Hinduism and Buddhism. If we assume that the writers put as much study and research...